Control device



NOV. 7, 1933. CONRAD 1,934,524

CONTROL DEVICE Filed Aug. 7, 1926 INVENTOR 500% Con/ad A'TTORNEY i atented Nov. 7, I933 r oric CONTROL DEVICE v Frank Conrad, Pittsburgh, Pa", assignor to West-w inghouse Electric & Manufacturing Company,- a corporation of Pennsylvania -Appiication'August 7, 1926. Serial No..127,72l

3 Claims.

My invention relates to control devices, and it has particular relation to devices adapted to simultaneously control a plurality of resonant circuits. I I

One object of my invention is to provide a device for simultaneously varying the constants of a plurality of tuned circuits.

Another object of my invention is to provide, in a device of the type described, means whereby each of the simultaneously controllable circuits 'may be independently varied if desirable.

Another object of my invention is to so arrange a device for simultaneously varying the constants of a plurality of tuned circuits that the adjustment of all circuits may conveniently be accomplished by one hand ofthe operator.

Another object of my invention is to provide, in a device of the type described, a plurality of manually operable control-elements closely adjacent to one another, whereby all such elements may be simultaneously operated by a single hand, or may be individually operated by separate fingers of the same hand.

Another object of my invention is to provide, in

a device of the type described, a frictionally operated coupling element between the individual control-elements, whereby two or more of such elements may be rotated by the rotation of a single one thereof.

There is, at the present time, a very pronounced trend toward apparatus adapted to simultaneously control a plurality of. tuned circuits in both radio transmitters and receivers. Such devices have met with'great popular favor and are generally known in the art as unicontrol devices.

It has been proposed to permit a slight amount of, lost motion between a master-control element and the individual tuning elements in order that each individual element may be more accurately adjusted. The use ofsupplementary-tuning elements for Vernier control has also been proposed but this introduces additional complications and is contrary to the general trend toward simplification of controls.

Perhaps the best known of the unicontrol devices of the prior art is that disclosed in the.

patent to J. L. Hogan, No. 1,363,319, in which a plurality of condensers are operated simulta-.

neously by link-motion. My invention is an im= 5O stead of the relatively-slight individual-element variation permitted by that device, it provides for complete zero-to-maximum adjustment of each.

In a preferred form, my invention comprises a provement over the-device of Hogan, andf'inplurality of variable-reactance devices, such condensers, variometers, or resistors arranged with their movable portions 'co-axial. Each movable portion is provided with a relatively large indicating andoperating dial, and the dials are so arranged as to be closely adjacent. I pro- Vide each pair of dials with means whereby it frictionally engages a neighboring dial, making it possible to, move two or more dialsby applying a force to but one of them, or, by restraining the motion of one dial, to separately move the others.

The novel features which I believe to be characteristic of my invention are set forth. with particularity in the appended claims. My invention itself, however, both as to its organization and its method of operation, will best be understood by reference to the following description, taken in connection with the accompanying drawing, in which,

Fig. .1 is a diagrammatic view of a radio receiving circuit equipped with a preferred form of my invention,

Fig. 2 is an elevational view, partly in section, of a'preferred form of my invention,

Fig. 3 is an endelevation view of one of the control dials, showing the friction-clutch, and

Fig. 4 is a view, partly in elevation, and partly in section, of a modified form of my invention.

Referring specifically to Fig. 1, a radio-receiving system 1 of the superheterodyne type, com prising a thermionic amplifying device 2, a thermionic detecting device 3, a thermionic oscillation-generating device 4, a second amplifying device 5, and a second detecting device 6, is provided with an input circuit comprising a loop '7 shunted by a tuning condenser 8. The inputcircuit of the first detecting device 3 is tuned by a condenser 9, and the frequency of the oscillations. generated by the generating device 4 is governed by the setting of a third condenser 11.

The specific circuit illustratedhas no particular bearing on my invention, being shownmerely as one of a plurality of circuits to whichmy invention is applicable. Persons skilled inthe art are thoroughly familiar with the arrangement and operation of super-heterodyne circuits of the type shown, and, for this reason, the circuit per se is not described in detail.

.The condensers 8, 9 and '11 are so arranged that the axesof their rotors are in substantial alignment, a plurality of operating dialslZ, 13, 14 and 15 being employed for the purpose of adjusting the angular relation of the rotors to the co-acting stators. A device 16, carried by the dial 12, makes frictional contact with the dial l3, and a device 17, carried by the dial 14, makes frictional contact with the dial 15.

The exact construction of the frictional devices 16 and 17 will be explained later in connection with the description of Fig. 2.

Referring now to Figs. 2 and 3, a panel 21, which may be the vertical or slanting-front panel of a radio cabinet, is provided with an opening 22. A plurality of condensers, 23, 24 and 25 are affixed to the rear surface of the panel 21 by means of screws 26 or analogous fastening devices. Each condenser comprises a plurality of stationary plates 27 and a plurality of movable plates 28. The condensers preferably have the same maximum and minimum capacity and are of the type known as straight-line-frequency condensers.

The movable plates of the condenser 23 are mounted on a shaft 29 and the movable plates of condenser 24 on a shaft 30, while the movable plates of the condenser 25 are carried by a shaft 31. The shafts 29, 30 and 31 are disposed in substantial alignment, an insulating coupling device 32 serving to connect shafts 29 and 30.

The shaft 30 of condenser 24 carries a relatively large knurled dial 33, provided with a cylindrical element 34 upon which wave-length or frequency indicia may be marked. The shaft 7 31 of the condenser 25 also carries a large knurled dial 35 and a cylindrical element 36, the two cylindrical elements 34 and 36 being disposed adjacent to each other. Both dials 33 and 35 project through the opening 22 in the panel 21, and are sufficiently close to each other to be rotated by the fingers of one hand to adjust the condensers.

A resilient element 37, having a T-shaped portion 38, provided with a layer 39 of felt, or analogous material, is afiixed to the inner surface of the dial 33 by means of bolts 41 and spacing washers 42. A cylindrical element 43 bears against the inner portion of the spring element 37 and is held firmly in engagement therewith by means of an adjusting screw 44.

The felt covering 39 of the T-shaped portion 38 bears on the inner surface of the cylindrical element 36 carried by the dial 35 with sufiicient friction to transmit power thereto from the dial 33. I

The insulating coupling device 32 may be replaced by a plurality of indicating dials, if desired, as shown in Fig. 1, or, if circuit conditions permit, the shafts 29 and 30 may be combined into a single shaft carrying the rotors of the condensers 23 and 24.

It is believed to be apparent that the shaft 30 could be made hollow, permitting the shaft 29 to extend therethrough and carry an individual indicating dial adjacent to the dials33 and 35.

This modification which is illustrated in Fig. 4, comprises the dials 33 and 35 for controlling the condensers 24 and 25 and an additional dial 50 for controlling the condenser 23'independently of the remaining condensers if desirable.

Other modifications of my invention that may be resorted to by those skilled in the art in the event that it is considered desirable to provide each condenser with an individual dial and to locate all of the dials adjacent to one another are believed sufficiently obvious to not require further illustration.

In the operation of a device constructed as illustrated in Fig. 2, the dial 35 may be held against rotation by the operator, and the dial 33 be rotated to adjust the condensers 23 and 24 in unison. As soon as the condensers 23 and 24 have been adjusted to the point at which the tuning of the circuits associated therewith is such as to cooperate with the circuit controlled by condenser 25, the dial 35 may be released by the operator, and further power applied to the dial 33 will, by virtue of the frictional engagement of the resilient element 3'7 with the inner surface of the cylindrical element 36, cause rotation of dial 35 and consequent adjustment of condenser 25 in unison with condensers 23 and 24.

The dials 33 and 35, as well as a dial controlling the condenser 23, may be so positioned as to be easily operable by the fingers of a single hand.

By my invention, I have thus provided a device for controlling tuned circuits that is simple and practical. Each circuit may be individually tuned over its entire range, if desired, or all circuits may be tuned in unison by the motion of a single control-element.

Although I have shown and described my invention as applied to a plurality of variable condensers, it is believed obvious that variable inductors, or resistors, or a plurality of variable elements of differing characteristics, may be controlled in the same manner.

It is believed to be also apparent that the general principles herein disclosed may be embodied in many other organizations widely different from those illustrated and described, without departing from the spirit of my invention. It is my intention, therefore, that my invention be limited only insofar as is necessitated by the prior art and by the appended claims.

I claim as my invention:

1. In combination, a panel having an opening therethrough; a plurality of reactance devices supported adjacent one surface of said panel, control means for said devices, said control means comprising a plurality of vertically disposed dials extending through said opening, and means for transferring power from one of said dials to another of said dials.

2. In combination, a plurality of variable condensers each comprising a stationary element and a movable element, actuating means for said movable elements comprising relatively large manually operable drums positioned adjacent to one another, and means comprising a spring element carried by one of said drums and frictionally' engaging the other of said drums for conveying'power to another of said drums at the option of the user.

3. In combination, a plurality of reactance devices, each comprising a stationary element and a movable element, control means for certain of said movable elements comprising vertically disposed drums, said drums being supported adjacent one another in axial alignment, and friction means mounted interiorly of one of said drums and maintained in 'slidable frictional engagement with the inner surface of another of said drums to convey motion therebetween.

- FRANK CONRAD. 

